document.write( "Question 131401: I can't seem to figure out this problem. Could I please have some help in figuring it out. Bobby and Mike have a summer job mowing the school yard. One riding mower takes 7 hours and the other takes 6 hours. If they are both used to mow the yard, how long will it take. \n" ); document.write( "

Algebra.Com's Answer #95945 by Edwin McCravy(20059) $\"\"$ $\"About$

You can put this solution on YOUR website!
I can't seem to figure out this problem. Could I please have some help in
\n" ); document.write( "figuring it out. Bobby and Mike have a summer job mowing the school yard. One
\n" ); document.write( "riding mower takes 7 hours and the other takes 6 hours. If they are both used
\n" ); document.write( "to mow the yard, how long will it take.\r
\n" ); document.write( "\n" ); document.write( "

\r\n" );
document.write( "Here's how to do it without algebra.  Then we'll do it with algebra.\r\n" );
document.write( "\r\n" );
document.write( "If both mowers were to run continually for 42 hours, the 7-hr mower would have\r\n" );
document.write( "mowed 6 lawns and the 6-hour mower would have mowed 7 lawns, a total of 13\r\n" );
document.write( "lawns.  So it takes them both together 42 hours to mow 13 lawns, then dividing\r\n" );
document.write( "42 by 13, it takes them  or  hours to mow 1 lawn.\r\n" );
document.write( "\r\n" );
document.write( "With algebra:\r\n" );
document.write( "\r\n" );
document.write( "Make this chart:\r\n" );
document.write( "\r\n" );
document.write( "                No. of lawns       Rate in lawns/hr     Time\r\n" );
document.write( "Slower mower  \r\n" );
document.write( "                                                      \r\n" );
document.write( "Faster mower           \r\n" );
document.write( "\r\n" );
document.write( "Both together                                               \r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Let x be the answer, the time for both together to mow 1 lawn.\r\n" );
document.write( "So fill in x for the time for \"both together\" and 1 for the No. of lawns.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "                No. of lawns       Rate in lawns/hr     Time\r\n" );
document.write( "Slower mower                                                        \r\n" );
document.write( "\r\n" );
document.write( "Faster mower                                                 \r\n" );
document.write( "\r\n" );
document.write( "Both together         1                                   x\r\n" );
document.write( "\r\n" );
document.write( "

\n" ); document.write( ">>...One riding mower takes 7 hours and the other takes 6 hours...<<
\n" ); document.write( "

\r\n" );
document.write( "So fill in the slower mower's time as 7 hrs and the faster mower's time\r\n" );
document.write( "as 6 hours.  Also since this is their time for mowing 1 lawn, fill in\r\n" );
document.write( "1 for the No. of lawns. \r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "                No. of lawns       Rate in lawns/hr     Time\r\n" );
document.write( "Slower mower          1                                   7         \r\n" );
document.write( "\r\n" );
document.write( "Faster mower          1                                   6 \r\n" );
document.write( "\r\n" );
document.write( "Both together         1                                   x\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Next, use  to fill in\r\n" );
document.write( "the three rates:\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "                No. of lawns       Rate in lawns/hr     Time\r\n" );
document.write( "Slower mower          1                                  7         \r\n" );
document.write( "Faster mower          1                                  6 \r\n" );
document.write( "Both together         1                                  x\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Now we form the equation by:\r\n" );
document.write( "\r\n" );
document.write( "[Rate of slower] + [Rate of faster] = [Rate of both together]\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "         \r\n" );
document.write( "\r\n" );
document.write( "Can you solve that?  If not post again asking how.\r\n" );
document.write( "\r\n" );
document.write( "Answer:  or  hrs.\r\n" );
document.write( "\r\n" );
document.write( "Edwin

\n" ); document.write( " \n" ); document.write( "

\n" );